Frankfurt Quasar Monitoring

PG 1351+640
Object data

  Cross-Identifications   2XMM J135315.8+634546, PGC 49340, LEDA 49340
  IRAS 13517+6400, SDSS J135315.83+634545.6
  FBS 1351+640, QSO B1351+640, 1351+640
  NVSS J135315+634545, PG 1351+64
  Equat. coordinates   RA  13 53 15.7     DE  +63 45 46     (J2000)
  Constellation   Draco
  Type   QSO
  Redshift (2)   z=0.088
  Distance (2) (3)   357 Mpc
  Total mag range (mv) (4)   14.0 - 15.2
  Catalog Magnitude (1)   14.28
  Absolute Magnitude (1)   -24.1 MB
  Light Travel-Time (2)   1.115 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Co-Moving Radial Distance
(4) Literature

Finding chart


Comparison stars

star B V Rc Ic
A 13.066 (0.011)
12.652 (0.020)
12.404 (0.017)
11.860 (0.031)
B 14.399 (0.006)
13.192 (0.010)
12.484 (0.001)
11.835 (0.029)
C 15.891 (0.049)
14.388 (0.013)
13.307 (0.004)
12.297 (0.173)
D 15.608 (0.009)
14.716 (0.002)
14.196 (0.004)
13.715 (0.006)
E 15.983 (0.015)
15.319 (0.002)
14.848 (0.008)
14.539 (0.010)
F 16.293 (0.011)
15.756 (0.005)
15.336 (0.007)
14.875 (0.071)
comparison stars from Gonzŕlez-Pérez et al. 2001, AJ, 122, 205

Colour chart A
Credit: SDSS  /  Size 13´× 13´ /  Chart by S. Karge
Colour chart B
This image from SDSS shows the elliptical host galaxy of quasar PG 1351+640
(apparent diameter 20") as well as the adjacent galaxies G1 and G2
Credit: SDSS  /  Size 3´× 3´ /  Chart by S. Karge

Light curve


PG 1351+640 is a small amplitude variable object in Draco, only 1.4° SW of Alpha Draconis. The designation PG 1351+640 refers to the Palomar-Green Bright Quasar Survey (PG), where this object was discovered as a blue stellar object in 1976. Follow-up spectral analysis revealed a Seyfert 1-spectrum, which led to the quasar classification. The elliptical host galaxy (PGC) has an apparent diameter of 20", showing signs of disturbances. The total flux of PG 1351+640 is dominated by UV- and IR-emissions (FBS/IRAS). On the other hand, this quasar is a very weak radio source.

Colour chart B shows two galaxies north-west of quasar 1351+640, denoted as G1 and G2. G1, a two-arm spiral, has the same redshift as the QSO (z=0.088), so there might be tidal interactions between G1 and the quasar host. Edge-on galaxy G2 instead may not be involved, as it shows a redshift of only z=0.077.

[G1 = 2MASX J13531197+6346080 = SDSS J135312.07+634608.2, z=0.088, 357 Mpc, 18.0g, 0.20´x0.15´]*
[G2 = 2MASX J13530685+6346431 = SDSS J135306.72+634642.5, z=0.077, 315 Mpc, 17.2g, 0.75´x0.11´]*
*Data from NASA/IPAC Extragalactic Database
PG 1351+640 is a small amplitude variable object with a total range of only about 1 magnitude in the optical. Visual observers need at least an 8- to 10-inch telescope to glimpse this stellar object. Observers with large aperture telescopes and higher powers may recognize the object becoming increasingly star-like, a clear sign of the quasar host. Tracking down PG 1351+640 is quite easy due to its proximity to Alpha (11) Draconis (1.4° NE of QSO) and 10 Draconis (4m.6), only 1° N of the quasar.
CCD observers, as well as visual observers, shall use the comparison stars given above.
Both CCD and visual observers are advised not to use comparison star C=14.388 mv solely for brightness estimations, as this star is considerably red (B-V 1.503) !

An interesting deep sky object can be observed some 2.8° south of the quasar. NGC 5308 is a pretty bright edge-on galaxy, easily detectible with an 8-inch telescope or larger. Only 50´ further to the south, another galaxy may attract your interest: NGC 5322, a bright 11.1-mag elliptical galaxy. Some 10° to the south we reach M101, a bright and large showpiece spiral galaxy in UMa. The latest supernova SN2011fe occurred in M101 in late August 2011 and reached 10th magnitude.

Observers who like to
continue their deep sky session with some quasi-stellar objects may first turn to BL Lac object MRK 180, a bright 14-mag object at a distance of about 0.6×109 light-years, some 15° E.
Another bright 14-mag quasar, PG 1411+442, is located some 20° S at a distance of about 1.1×10
9 light-years.

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Sloan Digital Sky Survey

© Stefan Karge  /  last obs. 2023-01-25